Manage FortiSwitch Topology Issue

I have the following scenario, Fortigate towards FortiSwitch 2048F in MCLAG, and access switches connected to both 2048F.  I was able to configure MCLAG, and add 2 access switches without issue. Meaning GUI topology on managed fortiswitch is showing what is expected. 

But as soon as I add the 3rd access switch, the topology changes and one of my MCLAG interface went missing on the GUI as well as the MCLAG grouping.

I am using 7.4.8 on FortiGate, 7.6.2 on FortiSwitch. I am only using the GUI on FortiGate to create all of this.